Exudate trap for shells



April 14, 1942. w. o. SNELLING EXUDATE TRAP FOR SHELLS Filed March 18, 1939 ww/eraJM/ ATTORN EY Patented Apr. Mi, 19422 ii it i i want EXUDATE TRAP FOR SHELLS Walter O. Smelling, Allentown, Pa., assignor to Trojan Powder Company, Allentown, Pa.

6 Claims.

This invention relates to shell for explosive material and particularly to military fragmentation or demolition units such as high explosive shell, drop bombs, torpedoes, and the like. More especially, the invention relates to shells, for liquid-exuding explosives, comprising a recess for receiving the exuded liquid.

Because trinitrotoluene is a very satisfactory explosive for most types of such demolition units, the invention will be described in connection with the use of trinitrotoluene as the explosive charge.

It will be understood that cast trinitrotoluene is quite insensitive and therefore, is detonated ordinarily by an intermediate charge of a more sensitive material, the latter being known as the booster charge and consisting usually of tetryl contained in a booster casing. The detonation of the booster charge is initiated by the action of a detonator or by other suitable means, when the shell strikes an object or in a selected interval thereafter, the detonation of the booster charge explodes in turn the main explosive in the shell.

When such loaded shells are stored in magazines for a long time, they are sometimes stood upon their bases, the end that is then uppermost being the one that is the forward end when the shell is fired.

Experience has shown that, in such an assem bly of trinitrotoluene, booster, and the metal parts constituting the shell and said casing, there may develop over a period of years some impairment of the functioning of the loaded ammunition, if trinitrotoluene of lower melting point than 802 C. has been used. After twenty years, for instance, a certain number of shells out of every thousand may fail to detonate properly under normal conditions of use.

This difficulty has been traced to the exudation of a dark-colored, oily liquid from the trinitrotoluene and its collection at the surface of contact between the booster casing and main charge, so as to produce a cushioning film at that critical surface, or to its infiltration into the booster casing and desensitization of the booster charge. Furthermore, the exudate tends to escape through the screw head of the shell under the effect of the pressure caused by temperature changes during storage of the filled shell. In other words, as the trinitrotoluene, which is ordinarily cast in place and completely fills the shell, is subjected to alternate cooling and warming, the expansion produced on warming tends to force the exudate from the shell. When so forced from the shell, the exudate is objectionable both from the standpoint of cleanliness and from the standpoint of safety.

While the invention is not limited to any theory of explanation of exudation, it is noted that the exudate is commonly considered to be a mixture, probably the eutectic, of isomeric trinitrotoluenes and some impurity, such as one or more of the clinitrotoluenes. The liquid exuded is sometimes called tarry matter or dark-colored exudate.

It is an object of the invention to provide a shell which when loaded will be less liable to loss of sensitiveness in storage. Another object of the invention is to provide a shell having a minimized tendency to leakage of liquid material therefrom. Other objects and advantages of the invention will appear from the detailed description that follows.

Briefly stated, the invention comprises a shell provided with a trap for receiving liquid, as such liquid may be exuded from a solid explosive, the term trap when used herein denoting a recess adapted to remain unfilled when the remainder of the space within the shell is filled with a molten explosive such as trinitrotoluene and the explosive then solidified.

The invention will be more particularly illustrated by description in connection with the attached drawing, to which reference is made.

All of the figures are partly in section and are broken away for clearness of illustration. Parts not shown in detail are conventional.

Fig. 1 shows a shell provided with trap for exudate.

Fig. 2 shows a shell having traps in different locations and of different shapes from the trap of Fig. 1.

Fig. 3 shows a filtering element disposed over the entrance to the trap and an absorbent filling within the trap of Fig. 1.

Fig. 4 illustrates on a somewhat larger scale a portion of the assembly of kind shown in Fig. l, with a side entrance to the trap.

Fig. 5 shows an assembly in which the booster casing is provided with channels communicating with the trap or traps.

There are shown in the several figures a shell I0 enclosing the space H for the solid liquidexuding explosive, space I2 for the booster charge and the booster casing i3, the casing except as noted later being the conventional metal retainer that is in common use in shells for artillery of '75 mm. gage or larger.

The nose of the shell is designated generally by the reference character M. This forward end includes the timer or fuse i5 and the adapter it which is threaded into the forward portion of the main body of the shell. Supported by the adapter and ordinarily passing through the hole therein and fitting therewithin is the booster casing l3 previously referred to.

In the preferred embodiment of the invention, the front portion of the shell in advance of the space for the main explosive charge is the part of the shell that is provided with the trap or recess H. In this embodiment the trap or recess may define a space that is an annular groove opening rearwardly. It communicates with the space for the said explosive charge within the shell. In the filled shell, this trap or recess'communicates with the trinitrotoluene, so as to receiveliquid exuded therefrom.

Suitably, there is disposed over the entrance to the recess a filtering element or assembly is (Fig. 3) including, for example, a perforated plate or grid for restricting the entrance of the solid explosive into the trap while permitting liquid exudate to enter. This assembly may include a pair of perforated plates with a filter cloth, such as one of woven wire, therebetween. The whole filtering assembly may be held in position by spot welding (not shown) or in other suitable manner.

Also, the space defined by the recess may be largely or completely filled by a granular, finely divided, or fibrous absorbent 19, as, for example, diatomaceous earth, pumice, gun-cotton, or crystals of potassium nitrate or like material. When the latter two fillers are used they form an explosive mixture with the absorbed exudate.

The trap of Fig. 4 is closed at the rear by an imperforate element such as a metal plate 25] 1 spot-welded in position; entrance to the trap is by means of a lateral opening 2i or several such lateral openings extending, in spaced relationship to each other, through the adapter, from the outer surface thereof inwardly to the trap. With the entrance to the trap so located, direct thrust of the trinitrotoluene, on expansion, against the entrance is either reduced or avoided.

There is a particular advantage in-the location of the trap in advance of the space for receiving the explosive, at the front end of the shell, and between the shelland the booster casing, in approximately the position illustrated in Figs. 1, 3, 4, and 5. In this position, "the trap is conveniently available to the exudate which always tends to work toward the outer end of the booster casing and toward the booster end or'ends of the shell. Also, danger from the filling of the space on set-back of the explosive when the projectile is fired is avoided when the recess is at the front end of the shell, as, for instance, in

the rear face of the adapter it.

For some purposes there may be used the modification of the invention shown in Fig 2, the trap being within or adjacent to the booster casing. Thus, a trap 22 may be at the base of said casing, so as to constitute practically an extension of thecasing. Thistrap is apertured, preferably perforated on its side and may be filled with absorbent material of the kind recited above. The trap may be welded or otherwise attached to the end of the booster casing. Or, there may be provided a trap in the formof an annular groove 23 in the booster casing.

In connection with traps of the kind described, say, those illustrated at H and 23, there may be used a booster casing provided with channels or grooves 24 communicating with the trap or traps, as shown in Fig. 5. Under some conditions, there is thus facilitated delivery of the liquid exudate to the space or spaces for receiving it.

The traps may be formed in the appropriate part of the assembly in any convenient manner. Thus, the recess I! may be formed during shaping of the adapter or may later be cut therein. The bead or groove 23 may be pressed into sheet metal which is then formed into the tubular casing H3. The trap 22 may be separately made and then welded in position.

In filling the shell and assembling the various elements of the loaded ammunition, usual procedure is followed, except that parts provided with a trap are substituted for standard parts having'no trap. In those forms of my invention inwhich traps for liquid exudate form a portion of the body of the booster casing, and particularly where trapsfor liquid exudate take the form of annular grooves within the booster casing, it is contemplated that the space to receive the booster casing will be drilled into the explosive which has been introduced into the shell. in liquid condition and then allowed to solidify. While the invention has been illustrated by description in connection with the use of trinitrotoluene as the main explosive charge, the shells provided with the trap or recess may be employed for receiving other solid explosives that exude liquids on long storage, the principle of operation and the functioning of the trap being unaffected by the chemical composition of the exudate which is received within the trap.

Likewise there may be used another booster charge than tetryl and conventional shapes of shells other than those shown in the drawing, the terms shells or shell being used herein to include demolition units in general and projectiles in particular.

The word shell as used in this specification and in the claims is intended to broadly cover a rupturable metallic container for high explosive for military use, and to comprise such ordnance devices as high explosive projectiles, drop bombs, marine torpedoes, sea mines, and the like.

It will be understood also, that the details given are for the purpose of illustration, not restriction, and that variations within the spirit of the invention are intended to be included in the scope of the appended claims.

I claim:

1. A shell comprising a single-walled container for explosive, a solid liquid-exuding explosive charge substantially filling the container, a booster charge casing extending Within the container and into the explosive charge at the end thereof that is forward when the shell is fired, and a member located inside the shell, in proximity to the booster casing, and provided with a recess in front of the said forward end of the explosive charge, the recess being left unfilled during filling of the shell with explosive and being open to receive liquid exuded by the explosive during storage of the shell.

2. A shell as'described in claim 1 including a filtering member, disposed over the entrance to the said recess, providing passages for the entrance of the exuded liquid and restricting the entrance of solid explosive into the recess.

3. A shell as described in claim 1, the said member provided with the recess being in the form of a generally ring-shaped member extending around the-booster'casing and between the said casing and the wall of the container and the 6. A shell comprising a container, liquid-exuding trinitrotoluene substantially filling the container, a member mounted in the mouth of the container and provided With a recess exposed to said trinitrotoluene for receiving liquid exuded by the trinitrotoluene, and an absorbent material including a compound containing nitrogen and oxygen disposed in the said recess, the said compound being adapted to absorb and form an explosive mixture with the liquid exuded by the trinitrotoluene.

WALTER O. SNELLING. 

